Purebred Rescue
An excellent way to rescue a purebred dog.
Dandie Dinmont Terrier Club of America Rescue

Breed Clubs
National and local breed clubs are generally devoted to both protecting and promoting their favorite breed. You're not likely to get sugar-coated reports of a breed here, but it's an excellent source to get unbiased information on all aspects of the breed, from those who have devoted decades to its welfare.
Dandie Dinmont Terrier Club of America
Dandie Dinmont Terrier Club of Canada
Dandie Dinmont Terrier Club (U.K.)
Caledonian Dandie Dinmont Terrier Club
Finnish Dandie Dinmont Terrier Club (limited in English)
Dandie Dinmont Club of Sweden (no English)

Breed Standards
Serves as a quick look-up to find stats such as height, weight and color, more importantly the breed standard gives what the "ideal" dog should look like for that breed. This is the "image of perfection" for which all good breeders strive. There are five main standards for each breed. Four independent kennel clubs plus the international kennel club, FCI. (Not all breeds have standards with all five registries.)
American Kennel Club standard
United Kennel Club standard
Canadian Kennel Club standard
Kennel Club (U.K.) standard
F數ration Cynologique Internationale

Other Sites
Dandie Dinmont Terrier: Its History and Characteristics by Charles Cook (1885 book free online)
Dandie Online (German site devoted to the breed)